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NTTEDv STATES PATENT OFFICE.l

WILLARD S. WHITMORE, OF WASHINGTON, DISTRICT OF COLUMIA.

PAPER-PULP MOLD FOR STEREOTYPING.

SPECIFICATION forming part of Letters Patent No. 239,584, dated March 29, 1881.

Application niednuguswaieso. (No model.)

To all Awhom 'it may concern:

Be it known that I, WILLARD S. WHIT- MORE, of Washington city, District of Columbia, have invented a new and Improved Paper-Pulp Mold for Stereotyping; and I do hereby declare that the followin g is a full, clear, and exact description of the saine.

In the drawings, Figure l is a face view, and Fig. 2 a section through line m My invention relates to paper molds or mat# rices for casting stereotypeplates.

Heretofore paper molds have, in practice, generally been made up of alternate layers of unsized paper and sheets of tissue-paper pasted together, which, while damp and more or less plastic, receive the impression of the type, and after being set by baking form a matrix, into which the melted stereotype-metal is poured. The object of the tissue-paper in the composition of the mold is to give a body to the same and to prevent ragged edges from sticking up. In making this kind of molds the paper `of which the mold is composed has set once by drying, and is dampened when the mold is made. Now, I have found that it is not possible to reduce the paper, having once been set, to the proper condition ot` a plastic, no matter how damp it may be made, and

when an impression is taken in such a composition the proper'depth of impression is not obtained, and the tenacity of the tissuepaper on the face of the mold causes it todi-aw, so that the cups of the letters and the spaces between the same are not of sufficient depth and sharpness.

To remedy these objections I have constructed a new composite mold which isformed of a sheet of unsized paper, A, covered with a layer of paper-pulp, B, which has never been set by drying. I

In my plan I form the plastic by taking the pulp prepared as for making it into paper, and put a sufficient quantity into a sieve that is immersed in water withma little glue, gum, or other adhesive agent. The pulp is thoroughly l mixed with the water in such a manner as to prevent as far as possible the formation of a grain,7 or the general lay of the ber in any one direction. The sieve is then removed from the water and the water allowed to drain oli, when a piece of felt-cloth is laid upon the pulp deposited in the sieve. A board of the required size is then laid upon the felt-cloth and slightly pressed down to make the'pulp adhere more rmly to the cloth, when the sieve is reversed and the pulp removed upon the cloth by giving the sieve a slight tap upon some solid object. The water remaining in the pulp is further squeezed outV by pressure, when the pulp is laid upon a heavy piece of unsized or stereotype paper which has received a coating of paste made either of starch, our, or some albuminous substance, and allowed to stand a while under a light pressure, that the Y paste may combine more thoroughly with both the pulp or plastic and the heavy stereotypepaper. The matrix is now ready, and is treated as in the old style of beating with a brush, or rolled with a heavy iron roller, and put under a screw upon a steam heating or baking table and allowed to bake until it becomes perfectly dry. y

The principal advantage in my plan lies in the fact that it is a more perfect plastic, the ber of the pulp has not become set, or is in such a state as to admit of its conforming more read ily to the contour of the letters, entering more easily into the cups or bowls ot' the letters and around the hair-lines or in the minute spaces between the letters. It is also tougher, the mold being capable of giving more perfect casts, and is more simple in detail, requiring but one layer of pulp, while the old plan requies three or four layers of paper.

In defining my invention more clearly, I would state that I am aware of English Patent No. 1,934; of 1868, in which it is proposed to use paper or dry pulp for the same purpose. The dry pulp here referred to, however, is in reality nothing better than a blotting-paper, and its bers being set once by drying, it is subject to the same objection as the laminated structure, as its bers have a coherence which simple wetting will not overcome. I

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